Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [sqlalchemy]

The popular Python package. If your question is about python coding, ask it on StackOverflow. Questions with this tag should focus on database code or the DB engine.

SQLAlchemy is a Python SQL toolkit and Object Relational Mapper.

40 questions
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Performance of count(*) in subquery

Suppose we have the following queries: 1. SELECT COUNT(*) FROM some_big_table WHERE some_col = 'some_val' 2. SELECT COUNT(*) FROM ( SELECT * FROM some_big_table WHERE some_col = 'some_val' ) Does any of the previous queries perform better?…
McSonk
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2 answers

How to set a auto-increment value in SQLAlchemy?

This is my code : class csvimportt(Base): __tablename__ = 'csvimportt' #id = Column(INTEGER, primary_key=True, autoincrement=True) aid = Column(INTEGER(unsigned=True, zerofill=True), Sequence('article_aid_seq',…
Farhaan Patel
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SELECT query blocking writes in postgresql

We have a web application that sends emails with a queue worker. Before an email is sent we write to a table: INSERT INTO user_email (user_id, email_key, sent_at) VALUES ( 175413579283955991, 'reminder-2017-07-06', …
Michael Mattax
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2 answers

Operational Error on MySQL AWS RDS Instance

The heading pretty much describes it all, here are some more information on the Amazon RDS I am using. Engine: MySQL Community 8.0.28 Class db.r6g.large Multi-AZ no. The data volume is very small, not even a few megs, as I am just doing some PoC to…
Della
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2
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1 answer

How to efficiently store impressions in db?

For my flask app I need to track impressions, clicks on images. The current implementation that I have is impressions table where I store impression ip, useragent, geo location and all the relationships that I would like to have. So every impression…
martinktm
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1 answer

Database relationship inheritance

I have a vehicle sales store. In my store I sale many kind of vehicles for example cars and boats. And I would like to keep track of the sales. My vehicles has some attributes as: Arrive on store at (a date) Brand Model Color Type (is a car or is…
Lin
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Aurora PostgreSQL Severe Performance Degradation Under Concurrent Load

Environment: Database: AWS Aurora PostgreSQL ORM: SQLAlchemy API Framework: Python FastAPI Issue: I'm experiencing significant query performance degradation when my API receives concurrent requests. I ran a performance test comparing single…
Abhishek Tyagi
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1 answer

UPDATE incredibly slow on small PostgreSQL query - EXPLAIN ANALYZE causes it to hang

I'm trying to debug a very slow UPDATE query in one of my tables. The table name is beepers. It has 2486 rows and weighs 1204 MB. It has 18 columns and two indices: one on id and the other on friendly_name (a string with a legible name, i.e.…
R. Gosman
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SQL connection error in python webapp: "pandas.io.sql.DatabaseError: Execution failed on sql"

I have built a Webapp with python flask, that reads and writes to SQL tables. Typically in the morning, I receive an error regarding SQL query execution that looks like this (see logs snippet below). I'm quite new to web development and everything…
Liam
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1 answer

Unable to convert a table to hypertable due to unique index error

I am creating a table using Flask SQL Alchemy as follows: class Price(db.Model): __tablename__ = "prices" id = db.Column(db.Integer, primary_key=True) country_code = db.Column(db.String(2), nullable=False) value =…
some_programmer
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Storing many pandas DataFrames in SQLite with metadata

I need some help with designing a database. My aim is to persistently store a number of pandas DataFrames in a searchable way, and from what I've read SQLite is perfect for this task. Each DataFrame contains about a million rows of particle…
smcs
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1 answer

How to Bulk Insert sqlalchemy subclasses

I am trying to bulk insert SQL-Alchemy Subclasses into the parent table and their respective tables ie fruits tables -> Apple Table and so I insert a table of APPLE and it will insert both the row into the fruits table then give me the id of the row…
Nilesh Kesar
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UUID default value on PSQL

I'm creating my database tables inside a flask application via SQLAlchemy. According to this answer, my code should look like this: id = db.Column(db.CHAR(36), primary_key=True, server_default=str("uuid_generate_v4()")) which, after migrations and…
codeninja
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Multiple many-to-many database relations

SO told me to ask here, so this is just copy-pasted from over there We're making a database of anime. Every anime can be listed as having been made by an arbitrary number of studios, and every studio can have made an arbitrary number of anime. The…
Kahr Kunne
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How to cache queries in sqlalchemy just like I do it in mysql by using SQL_CACHE keyword?

I want to cache sqlalchemy, I have discovered that using keyword SQL_CACHE in mysql can be helpful in caching queries on demand. But how do I do it in sqlalchemy? Is it possible?
Jitin Maherchandani
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